This invention relates to an improved pliers for contracting band clamps. More specifically, this invention relates to pliers for contracting differing types of band clamps used to seal different types of sealing boots (such as constant velocity boots) around assemblies (such as a front wheel drive shafts) on which the boots are mounted.
Front wheel drive vehicles have long employed a special joint, the "constant velocity" or "CV" joint, to transmit rotation of a transaxle driven by an engine into rotation of the front, steerable wheels of the vehicle. The joint is called a CV joint because it ensures that, when the engine crank shaft rotates at a constant speed, the wheels rotate at a constant speed even as they are turned to steer the vehicle.
The CV joint is a fairly complicated assembly of drive shaft, cage, race bearings, ball bearings, output shaft, and lubricants. It must work smoothly and with minimum friction.
To keep dirt and other contaminants out of the joint and to retain lubricants, a flexible plastic or rubber boot or sleeve is mounted over the joint to seal the intersection of the joint and the axle or drive shaft. The boot has a complex tubular shape and encircles the CV joint. At least one end of the boot is retained on the CV joint by means of a band clamp. Thus, the CV band clamp is also circular to clamp the boot to the cylindrical shaft or housing of the CV joint.
There are several different types of CV boot clamps, which contract or tighten around the boot in various manners. Typically, however, CV boot clamps are applied about a CV boot and compressed against the boot by collapsing or folding over a portion of the clamp to reduce the circumference of the clamp against the periphery of the boot and thereby retain the boot on the CV joint or shaft.
Today, there are three prevalent ear types of boot clamps:
1. a normal duty ear clamp having two protruding ears on either side of a single "offset" or protrusion in the periphery of the clamp; a special clamp pliers grips the surface of the ears, and by compressing them together, reduces the circumference of the clamp;
2. normal duty ear clamps with a dimple in each ear; a special clamp pliers having a pin in each jaw penetrates the opposing dimples, and by closing the jaws, the offset collapses or compresses between the ears; and
3. extra heavy duty ear clamps that require compressing the offset by a specific, high torque reading.
Two such speciality pliers used to effect compression or diameter reduction of the CV boot clamp are (i) the hand operated pliers disclosed in U.S. Pat. No. 3,216,291, and (ii) the socket pliers shown in FIG. 5 of this specification.
The pliers disclosed in U.S. Pat. No. 3,216,291 ("the '291 pliers") are hand operated. Closing the '291 pliers by hand causes jaws to grip the sides of the offset and effect compression, thereby reducing the diameter of the band clamp. At the same time, as the jaws compress the offset, an anvil rams the compressed offset radially inwardly to form a T-shaped fold in the band. Such a T-shaped fold is usually stronger than an offset collapsed by jaws without radially ramming the offset with the anvil.
Another prior art tool is the socket pliers shown as "Prior Art" in FIG. 5 of this application. This tool does not have a thrust plate and is not hand operable to adequately and securely compress a band clamp about a CV-boot. Rather it is used to compress band clamps in conjunction with other tools.
The socket pliers is comprised of crossed arms, with a washer separating the arms at their intersection. Each arm has a socket in the end opposite the jaw. Each socket is reinforced with a square apertured reinforcing plate welded to each arm over the socket. The socket aperture is thus deepened or extended by the reinforcing plate.
To use the tool, a breaker bar is attached in the socket in one arm, and a torque wrench is attached in the other socket in the opposing arm. By forcing the breaker bar and torque wrench toward each other, the operator can apply a relatively high and measured amount of torque to compress the clamp against the boot.
Neither of these prior art tools is adequate for use as both a hand operated and torque-wrench-driven CV boot clamp pliers. Moreover, while the socket pliers tool is designed for torque-wrench operation, it does not provide any mechanism of ramming the offset as it is compressed between the jaws of the pliers. On the other hand, the '291 hand-operated tool provides a ramming mechanism but cannot be used to clamp at high specific torque readings and does not have any washer between the plier arms to reduce wear between the lever arms in high torque applications.
It is thus an object of the present invention to provide a unitary tool that can be alternatively hand operated or torque-wrench operated to compress a wider variety of boot clamps.
It is yet another object to provide such a tool that provides a mechanism for ramming the clamp offset radially as it is compressed between the jaws of the pliers. A still further object is to provide such a mechanism that also serves the function of a washer between the lever arms.
An additional object of this invention is to have a hand operable boot clamp pliers utilizing an economical lever arm that is light weight and reinforced and strengthened to accommodate a torque wrench or breaker bar.
Another object is to provide such a lever arm that is constructed of two sections joined together to define a reinforced and strengthened socket capable of receiving a torque wrench or breaker bar.
Yet another object is to provide an improved clamp pliers which is inexpensive, desirable, and easy to operate. These and other objects, advantages and features are described herein.